The mounting of non-standard electrical components to circuit boards has long been a problem. It is, moreover, a problem which has become increasingly perplexing as circuit miniaturization and standardization of printed circuit board terminal connections have made circuit board assembly less adaptable to hybrid connection techniques.
When printed circuit boards were first introduced, it was not uncommon for electronic components to be mounted to the boards by hand. Although the circuit conductors were printed on the printed circuit board, the electronic components tended to be discrete elements with individual leads that were soldered, usually by hand, to the printed circuit board conductors. Each circuit board was "custom made". Interconnections between the electronic components on the circuit board and external elements were made via conventional flexible wire leads or conductors. Where the electronic components were to be powered from an external battery (usually a replaceable battery), as in a portable radio, for example, a pair of wire leads were soldered to respective points on the circuit board and, at the other end, to a battery terminal connector or to a battery holder which was mounted remotely from the printed circuit board.
This technique for making connections to printed circuit boards was notably inefficient, requiring much hand wiring, soldering and assembly work, in addition to special packaging techniques that were required to mount and support batteries in a convenient package which also housed the printed circuit boards. Adding to the difficulty was the variety of sizes and shapes of the batteries employed.
With the ever-increasing trend toward miniaturization and standardization, hand wiring techniques have become unacceptable. This is because connections to and from printed circuit boards are preferably made via edge connectors on the printed circuit board; no flexible wire leads will be found on most modern printed circuit board assemblies. This, is of course, is desirable in order to achieve the objective of having printed circuit boards replaceable and interchangeable without interfering with permanent circuit connections.
In cases where an external battery is connected to the printed circuit board, at least one or more edge connectors must be dedicated to the battery and, as before, separate provisions must be made for mounting and securing the battery at a position remote from the printed circuit board. This is neither efficient nor desirable, since it requires additional edge connectors and, as before, separate physical support means to accommodate the battery on a remote assembly, chassis, frame, etc. Moreover, it is an additional advantage to have the battery affixed to the circuit board to be powered and replaceable therewith; usually this means that a circuit board can be removed from its normal connecting socket without destroying the dc source of power.
Today, there are many critical applications for batteries where the battery must supply power to printed circuit components. Examples are computer systems, microprocessor controls, single-chip microcomputers and volatile RAM's (random access, read and write memories). In these applications, the batteries provide a back-up source of power in the event of line power failures, the batteries continuing to supply power in the interim between power failure and restoration. Unless a back-up current independent of the line power source is made available to volatile RAM's, the entire memory of a computer can easily be destroyed upon even a momentary loss of power.
The present invention has as one of its objects the provision of a battery source which is compatible with printed circuit boards and the like. Specifically, it is to provide a rechargeable battery for insertion into any of a number of standard printed circuit boards, or into standard sockets or or receptables for semiconductor chips.
A further object of the invention is to provide a rechargeable cell and battery case combination which is reliable, rugged, and fully compatible with DIP (dual in-line pin) socket configurations.
Yet more general objects are to provide a plug-in battery containing one or more electrochemical cells, to provide a battery which is easily and cost-effectively assembled, and to provide a battery which is rechargeable, removable, replaceable and supportable by the electronic chassis, circuit board, etc. which is to be powered thereby.